{
  # how to string-format the option name;
  # by default one character is a short option (`-`),
  # more than one characters a long option (`--`).
  mkOptionName ? k:
    if builtins.stringLength k == 1
    then "-${k}"
    else "--${k}"
, mkOption ? k: v:
    if v == null
    then [ ]
    else [ (mkOptionName k) (lib.generators.mkValueStringDefault { } v) ]
}:
{
  toINI =
    {
      # parameter comment
      mkSectionName ? (name: libStr.escape [ "[" "]" ] name)
    , mkKeyValue ? mkKeyValueDefault { } "="
    }: attrsOfAttrs:
    mapAttrsToStringsSep "\n" mkSection attrsOfAttrs;
}